Ana Maria Macias 4/9/2015

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Hello,

I am creating a model abuot the demand of natural gas in Colombia, so I'm not taking into accout other fuels. During the process I found out that if there is some electricity generation with NG the demand of the industry sector is affected.

Due to this, I am not sure how to model the electricity generation, in the demand branch or in the transformation one. And how can I link this two sectors.

Thank you so much!

Ana Maria

Taylor Binnington 4/14/2015
 

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Hi Ana Maria,

I'm afraid I'm having trouble interpreting your question. Electricity generation is usually treated as a separate transformation module in LEAP, not as a demand sector.

Can you clarify you question, and include some details about how you've structured your tree in LEAP? Please also clarify what you mean by your Industry branch being affected by generation of electricity from natural gas. Thanks you,

Taylor

Ana Maria Macias 4/14/2015
 

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Hi Taylor,

My tree is really similar to the Freedonia example. In Colombia the electricity is mainly generated by hydro plant, so if the water levels are low the thermal plants have to start generating to cover the electricity demand. In this case, if the demand of natural gas of these thermal plants is too high, the industry has to use an other fuel for their production because the electricity generation is a priority.

Hope this makes it more clear.

Thank you so much,

Ana

Taylor Binnington 4/17/2015
 

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Hi Ana Maria,

Okay, so I understand that there is a finite supply at any time of natural gas, so that if electricity is generated using gas then it cannot be consumed at the same time by industry. Is that right?

Normally in LEAP, demand accounting is conducted before any transformation calculations are resolved. This means that demand calculations will inform how the transformation modules operate, but transformation calculations will not inform demand calculations. If you wish to create such a relationship, you will need to use the flexibility of LEAP's expressions to create a function that relates the natural gas consumption of your industrial demand branch to the natural gas consumption for electricity generation (in the transformation branches).

There is no 'correct' way to do this, so it's difficult for me to tell you how. Instead, I would ask you the following:

a) Over what time scale do these fluctuations in gas demand occur? Do the time slices you've set up match this time scale?

b) Is the reduction of industrial gas demand something that is important to capture during the same time slices that natural gas is being used to generate electricity? Or can you simply reduce the industrial average annual demand for gas?


But beware - if your historical data (entered in Current Accounts) already account for this effect, would you not be counting the reduction in gas demand twice if you try to explicitly model it?

Hope this helps,
Taylor

Ana Maria Macias 4/17/2015
 

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Hi Taylor,

Yes, you got it right.

Thank you for your advice, I'm not sure how to create the function but I will try.

About your quiestions:

a) These events do not occure very often, they depend on the intensity of a climate phenomena called "El Ni��o", and it usually last about 9 months, between the end of one year and the beginning of the next one.

b) Both sectors use a big amount of natural gas, but the problem is the transport. So when this situation occurs, the gas transport system does not have the characteristics to fulfill both demands. This is the reason why is better disconnect the industrial demand instead of the generation demand.

I don't have this effect on the historical data, because this climate effect does not always occurs with a strong intensity. But on one of my scenarios I wanted to assume that there is a strong one in a couple of years.

Thank you so much for your help!!!!

Ana

Taylor Binnington 4/23/2015
 

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Hi Ana Maria,

Have a look at this help file, which provides an introduction to expression-building in LEAP:

http://www.energycommunity.org/WebHelpPro/Concepts/Expressions.htm

Try to think of your problem from a modeling standpoint - while you've provided interesting context for the problem you're trying to model, it's not clear if it's important for you to capture the *variability* in industrial consumption of natural gas (and if so, then over what time-scale), or if it would be sufficient simply to reduce the annual demand, by representing the annual average amount of 'missing demand' in new scenarios which you could call "Strong El Nino", "Weak El Nino" etc.

Hope this helps,

Taylor